This invention relates to spherical junction elements for composable display structures.
Entirely spherical junction elements for composable display structures are known in the art.
Such entirely spherical junction elements are provided with a number of slots extending parallel to respective meridian planes of the sphere and one slot extending parallel to the equatorial plane of the sphere. In some of the slots web portions are provided to maintain the material connection between the parts of the sphere divided by the slots. Usually such web portions extend according to diameters of the sphere corresponding to the respective slot and meridian or equatorial plane. The slots are adapted to receive corner portions of plate elements forming the composable display strusture. The plate elements are usually of glass or of transparent plastic material, but may be made of any suitable material including metal or wood. The spherical junction element is preferably made of a plastic material.
Heretofore the different slots provided in the entirely spherical junction element were all perpendicular to each other so that the maximum number of coner portions the junction element was capable of connecting together, was 12, of which four corner portions were part of four plate elements lying in one single base plane and eight corner portions were part of eight plate elements perpendicular to the base plane and four perpendicular also to each other. Instead of some of the diametral web portions provided in the slots, pin configurations were provided to define stop portions for the edges of the relevant plates of the display structure. Such pin configurations could be easily cut away in order to provide a through slot if desired for cases where one of the plates is received in the through slot in an intermediate point of the plate edge.
A drawback of the entirely spherical junction elements of the known art is their unsuitability in those points of the composable display structure, where less than twelve plate elements converge with their corners in a single point in the manner defined by the slots of the entirely spherical junction element.
In such points where only three plate elements perpendicular to each other converge into a corner point of the display structure, it is evident that only three respective slots of the entirely spherical junction element will receive the respective corner portions of the plate elements of the composable display structure. The remaining slots of the junction element will thus remain unused and will project like a spherical protuberance from the corner of the display structure.
In order to obviate this drawback it has already been proposed to provide series of entirely spherical junction elements having a diversified number of slots provided therein, so that there was always the possibility to select an entirely spherical junction element with the needed number of slots for the portion of the display structure where the junction element has to be used, the remaining portion of the junction element remaining solid and protruding spherically from the considered point of the display structure.
It will be understood that this solution did not eliminate the drawback of the spherical protuberance of the junction element at the outside corners of the display structure.
The shortcoming of such spherical protuberances affected remarkably the possibility of use of a display structure provided with entirely spherical junction elements. In fact, when the display structure had to be supported on a base plate, this had to occur through the spherical protuberances of the junction elements provided on the bottom corners or edges of the display structure. Thus, on the one hand an interspace was formed between the supporting base plate and the bottom plate of the display structure and on the other hand it was not easy to fix the display structure on the base plate owing to the spherical shape of the protuberances resting on the base plate. In addition, owing to the spherical shape of the protuberances the entire load acting on such protuberances was concentrated in small spots, which could cause undesirable deformations on the base plate. Furthermore, in the interspace between the bottom plate of the display structure and the base plate impurities could easily accumulate which could not be cleaned away easily, without removing the entire display structure from the base plate.
Moreover, in cases where display structures had to be approached to vertical walls, owing to the mentioned spherical protuberances of the junction elements it was not possible to avoid a gap between lateral plates of the display structure and vertical walls against which the display structure had to be leaned. Similar gaps or interspaces are formed in cases where more display structures had to be arranged in contact to each other, so that the effective space of the display structures was reduced, in addition to the undesirable interspaces.